Our long-term goal is to develop novel targeted therapies for the treatment of lung cancer. Lung cancer is an extraordinarily challenging and difficult disease to treat with a high incidence among Americans, staggering death rate, and abysmal overall five-year survival. Specially, lung cancer killed an estimated 162,460 Americans in 2006, more than breast, prostate, colon, liver and kidney cancer combined. Lung cancer responds modestly, at best, to conventional therapies and even the minority of clinically significant responses are all too often short-lived with 15% overall five-year survival. The advent of targeted, biological therapies offers the most promising avenue for lung cancer treatment in the 21st century. Over the past seven years, our lab has focused extensively on the Wnt signaling pathway that plays important roles in biological processes ranging from embryogenesis to tumorigenesis. Aberrant activation of Wnt signaling is also strongly implicated in lung carcinogenesis. In non-small cell lung cancer, (NSCLC), the dominant disease histology, we demonstrated that Wnt pathway activation can occur in a myriad of ways: through over-expression of Wnt ligands and Dvl proteins, hypermethylation-silencing of secreted Wnt antagonists: sFRPs and WIF-1, and activation of the (non-canonical) JNK pathway. Building on our extensive work, especially our preliminary data of Wnt-2 overexpression in NSCLC suggesting a role of inhibiting Wnt-2 in targeted therapies, we now seek to develop novel Wnt-2 based therapies by screening and optimizing small-molecule inhibitors of the Wnt-2 expression through a reporter assay. We hypothesize that this blockade will induce apoptosis and halt the proliferation of Wnt-2-activated NSCLC cells. Our specific aims are: 1) To screen for and optimize a set of lead compounds based on their ability to downregulate Wnt-2 promoter activity and Gli/TAF9 dependent transcription activity in the in vitro NSCLC system;2) To assess the biological activity of lead compounds on Wnt-2 over-expressing NSCLC cell lines, and to explore molecular mechanisms of the lead compounds in the induction of apoptosis, suppression of proliferation, cell cycle arrest and down-regulation of target genes including Wnt genes;3) To assess the anti-tumorigenic activity of the lead compounds in a human xenograft model of NSCLC and to assess general toxicity, pharmacokinetics and pharmacodynamics of the lead compounds in mice;and 4) To identify direct target proteins bound by the lead compounds and assess their selectivity for one another, and to investigate the inhibitory effects of lead compounds on the Gli and Wnt-2 pathways in NSCLC cells. In summary, we propose to develop novel molecularly targeted therapies for human lung cancer, one of the most lethal tobacco-related diseases with an alarmingly high incidence and mortality in the U.S. One direction of future drug development is to identify compounds that can kill cancer stem cells, and our proposal to screen for small molecule inhibitors to interfere with the Wnt-2 transcription may represent a viable strategy to identify possible cancer stem cell targeted therapy. PUBLIC HEALTH REVELANCE:The Wnt signaling pathway is known to be aberrantly activated in human lung cancer which is the leading cause of cancer death in the U.S. with an overall five-year survival of only 15%. The heart of our proposal is translationally focused, specifically the development of novel and innovative small molecule inhibitors of the Wnt transcription as molecular-targeted therapies against lung cancer.